Systems and methods for leaflet cutting using a hook catheter

ABSTRACT

A system configured to cut leaflet tissue at a cardiac valve may comprise a guide catheter having a proximal end and a distal end, wherein the distal end of the guide catheter is steerable to a position above a cardiac valve. The system may also include a hook catheter having a proximal end and a distal end, the hook catheter configured to extend from the distal end of the guide catheter through a first orifice of the cardiac valve. Further, the system may comprise a cutting mechanism extending from the hook catheter, the cutting mechanism configured to cut a portion of leaflet tissue of the cardiac valve. Finally, the system may include a handle coupled to the proximal end of the guide catheter, the handle comprising at least one control operatively connected to the cutting mechanism.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 63/020,665, filed May 6, 2020, the entire contents of which areincorporated by reference herein.

BACKGROUND OF THE INVENTION

The mitral valve controls blood flow from the left atrium to the leftventricle of the heart, preventing blood from flowing backwards from theleft ventricle into the left atrium so that it is instead forced throughthe aortic valve for delivery of oxygenated blood throughout the body. Aproperly functioning mitral valve opens and closes to enable blood flowin one direction. However, in some circumstances the mitral valve isunable to close properly, allowing blood to regurgitate back into theatrium.

Mitral valve regurgitation has several causes. Functional mitral valveregurgitation is characterized by structurally normal mitral valveleaflets that are nevertheless unable to properly coapt with one anotherto close properly due to other structural deformations of surroundingheart structures. Other causes of mitral valve regurgitation are relatedto defects of the mitral valve leaflets, mitral valve annulus, or othermitral valve tissues.

The most common treatments for mitral valve regurgitation rely on valvereplacement or repair including leaflet and annulus remodeling, thelatter generally referred to as valve annuloplasty. One technique formitral valve repair which relies on suturing adjacent segments of theopposed valve leaflets together is referred to as the “bowtie” or“edge-to-edge” technique. While these techniques can be effective, theyusually rely on open heart surgery where the patient's chest is opened,typically via a sternotomy, and the patient is placed on cardiopulmonarybypass. The need to both open the chest and place the patient on bypassis traumatic and has an associated high mortality and morbidity rate.

In some patients, a fixation device can be installed into the heartusing minimally invasive techniques. The fixation device can hold theadjacent segments of the opposed valve leaflets together and may reducemitral valve regurgitation. One such device used to clip the anteriorand posterior leaflets of the mitral valve together is the MitraClip®fixation device, sold by Abbott Vascular, Santa Clara, Calif., USA.

However, sometimes after a fixation device is installed, undesirablemitral valve regurgitation can still exist, or can arise again. Forthese patients requiring re-intervention, the presence of a fixationdevice in their mitral valves can obstruct transcatheter mitral valvereplacement. These patients may also be considered too frail to tolerateopen-heart surgery, so they are left with no viable options to furtherimprove the function of their mitral valve.

Accordingly, it would be desirable to provide alternative and additionalmethods, devices, and systems for removing or disabling existingfixation devices in preparation for the installation of an artificial,replacement mitral valve. The methods, devices, and systems may beuseful for repair of tissues in the body other than heart valves. Atleast some of these objectives will be met by the inventions describedhereinbelow.

BRIEF SUMMARY OF THE INVENTION

Implementations of the present invention solve one or more problems inthe art with systems, methods, and apparatus configured to cut leaflettissue at a cardiac valve. The system may comprise a guide catheterhaving a proximal end and a distal end, wherein the distal end of theguide catheter is steerable to a position above a cardiac valve. Thesystem may also include a hook catheter having a proximal end and adistal end, the hook catheter configured to extend from the distal endof the guide catheter through a first orifice of the cardiac valve.Further, the system may comprise a cutting mechanism configured to cut aportion of leaflet tissue of the cardiac valve. Finally, the system mayinclude a handle coupled to the proximal end of the guide catheter, thehandle comprising at least one control operatively connected to theguide catheter, the hook catheter and/or the cutting mechanism.

A system for cutting leaflet tissue at a cardiac valve may comprise aguide catheter having a proximal end and a distal end, wherein thedistal end of the guide catheter is guided to a position above a cardiacvalve transseptally or transapically. The system may further include ahook catheter having a proximal end and a distal end, wherein the hookcatheter is routable through the guide catheter and configured toselectively extend beyond the distal end of the guide catheter through afirst orifice of the cardiac valve. Also, the system may comprise acutting mechanism routable through the guide catheter and the hookcatheter and configured to cut a portion of leaflet tissue of thecardiac valve.

A method of cutting cardiac valve tissue at a cardiac valve within abody may include positioning a guide catheter, having a proximal and adistal end, within the left atrium transseptally such that the distalend of the guide catheter is positioned above a cardiac valve. Themethod may also comprise routing a hook catheter through the guidecatheter such that the hook catheter extends distally beyond the distalend of the guide catheter through a first orifice of the cardiac valve,wherein the cardiac valve is associated with an interventional implantthat approximates adjacent leaflets of the cardiac valve, and a cuttingmechanism extends from the hook catheter. The method may furthercomprise positioning the hook catheter to place the cutting mechanisminto contact with leaflet tissue located adjacent to the interventionalimplant and actuating the cutting mechanism to cut at least one leafletof the approximated adjacent leaflets.

Additional features and advantages of exemplary embodiments of theinvention will be set forth in the description which follows, and inpart will be obvious from the description, or may be learned by thepractice of such exemplary embodiments. The features and advantages ofsuch embodiments may be realized and obtained by means of theinstruments and combinations particularly pointed out in the appendedclaims. These and other features will become more fully apparent fromthe following description and appended claims or may be learned by thepractice of such exemplary embodiments as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which the above-recited and otheradvantages and features of the invention can be obtained, a moreparticular description of the invention briefly described above will berendered by reference to specific embodiments thereof which areillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are not thereforeto be considered to be limiting of its scope, the invention will bedescribed and explained with additional specificity and detail throughthe use of the accompanying drawings in which:

FIG. 1 illustrates an embodiment of a delivery system that may beutilized for guiding and/or delivering a cutting mechanism to a cardiacvalve;

FIG. 2 is perspective view of an embodiment of a cutting mechanismaccording to the present disclosure shown in use in association with ahuman heart;

FIG. 3 is a perspective view of another embodiment of a cuttingmechanism according to the present disclosure shown in use inassociation with a human heart;

FIG. 4 is a top perspective view of the cutting mechanism of FIG. 3shown in use in association with a human heart; and

FIG. 5 is a perspective view of yet another embodiment of a leafletcutting system according to the present disclosure shown in use inassociation with a human heart.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Implementations of the present invention solve one or more problems inthe art with systems, methods, and apparatus configured to cut leaflettissue at a cardiac valve. More specifically, at least one embodiment ofthe present invention the system may comprise a guide catheter having aproximal end and a distal end, wherein the distal end of the guidecatheter is steerable to a position above a cardiac valve. The systemmay also include a hook catheter having a proximal end and a distal end,the hook catheter configured to extend from the distal end of the guidecatheter through a first orifice of the cardiac valve. Further, thesystem may comprise a cutting mechanism extending from the hookcatheter, the cutting mechanism configured to cut a portion of leaflettissue of the cardiac valve. Finally, the system may include a handlecoupled to the proximal end of the guide catheter, the handle comprisingat least one control operatively connected to the cutting mechanism.

FIG. 1 illustrates an embodiment of a leaflet cutting system 100, whichcan include a delivery system 102 that may be utilized for guidingand/or delivering a cutting mechanism to the cardiac valve. In at leastone embodiment, the delivery system 102 includes a guide catheter 105having a proximal end 140 and a distal end 115. The delivery system maycomprise a handle 110 positioned on the proximal end 140 of the guidecatheter 105. The guide catheter 105 may be operatively coupled to thehandle 110. The guide catheter 105 may include a steerable portion 117near the distal end 115 that can be steerable to enable the guiding andorienting of the guide catheter 105 through a patient's vasculature to atargeted treatment site, such as a mitral valve. For example, the handle110 may include at least one control 120 (e.g., a dial, a switch, aslider, a button, etc.) that can be actuated to control the movement andcurvature of the steerable portion 117 of the guide catheter 105.

In at least one embodiment, the at least one control 120 is operativelycoupled to one or more control lines 125 (e.g., pull wires) extendingfrom the handle 110 through the guide catheter 105 to the distal end 115of the guide catheter (e.g., through one or more lumens in the guidecatheter 105). Actuation of the at least one control 120 may adjust thetensioning of one or more of the control lines 125 to steer the guidecatheter 105 in a desired curvature and/or direction. FIG. 1 shows thehandle 110 as having a single control 120, however, additional controlscan be provided, as needed, to curve/steer the steerable portion 117 inmultiple directions and/or planes. Alternatively, a handle 110 maycomprise more than one control 120 associated with any number of controllines 125. In at least one embodiment, the at least one control 120 canadjusts four or more control lines 125 to selectively controldirectional movement and/or curvature of the steerable portion 117 ofthe guide catheter 105.

While control lines or wires are described at various points in thisapplication, it should be understood that references made throughoutthis application to control lines or wires may be a single wire orplurality of wires including or made of steel, titanium alloy, aluminumalloy, nickel alloy, other metals, a shape memory material (such as ashape memory alloy or shape memory polymer), inorganic polymer, organicpolymer, ceramic, carbon materials, or other flexible material withsufficient tensile strength. For example, a control line 125 may be asteel cable. In another example, a control line 125 may be amonofilament suture. In another example, a control line 125 may be amultifilament suture. In yet another example, a control line 125 may bea braided suture.

It is desirable for guide catheter 105 to provide an adjustable distalend 115, which is capable of being positioned within a target bodycavity in a desired orientation. Guide catheter 105 should have a largelumen diameter to accommodate the passage of a variety of devices, suchas the various embodiments of the cutting mechanisms discussedhereinafter, and should have good wall strength to avoid kinking orcollapse when bent around tight curves, and should have good column,tensile, and torsional strength to avoid deformation when the devicesare passed through the lumen and torqued or translated. Guide catheter105 should provide for a high degree of controlled deflection at itsdistal end 115, but should not take up significant lumen area to allowfor passage of interventional devices, such as the cutting mechanismsdiscussed below. Further, guide catheter 105 should be able to bepositioned in a manner which allows compound curves to be formed, forexample curvature within more than one plane. Such manipulation shouldalso allow fine control over distal end 115 to accommodate anatomicalvariations within the same type of body cavity and for use in differenttypes of body cavities.

The guide catheter 105 may comprise a main body made of or including aflexible material. The main body may be made of or include a variety offlexible materials, such as thermoplastic elastomers (TPE). In someembodiments, the main body may be a polyether block amide (PEBA orPEBAX). The main body may have a constant durometer or may have varyingdurometer that varies along its longitudinal length or that varies indifferent portions of the body. For example, the main body of guidecatheter 105 may be made of or include a body material having adurometer of 25D to 75D. In another example, the main body of guidecatheter 105 may be made of or include a body material that has adurometer of about 45D. In at least one embodiment, the body materialmay include PEBAX 4533. In at least another embodiment, the bodymaterial may include PEBAX 3533.

The guide catheter 105 preferably defines a central lumen, extendingaxially through its entire length, through which other elongateelements, such as the cutting mechanisms may be inserted for accessing atreatment site. The central lumen may also include a central lumenlining on an inner surface thereof. In some embodiments, the centrallumen lining may be a protective material that protects the interiorwalls from damage due to another element of the elongated member movingthrough or within the central lumen. In other embodiments, the centrallumen lining may include a lubricious coating that reduces frictionbetween the interior wall and another element of the elongated membermoving through or within the central lumen. The central lumen lining mayinclude PEBA, polytetrafluoroethylene (“PTFE”), polyetheretherketone(“PEEK”), other polymers, thermoplastic polyurethane (“TPU”),polyethylene with pebble stone surface, silicone oil stainless steel,Nitinol, other metals, or combinations thereof. In at least oneembodiment, the central lumen lining may include a plurality of PEBAmaterials having different durometers.

In other embodiments, the guide catheter 105 may also have an outerlayer. In some embodiments, the outer layer may be made of or include asingle material or may be made of or include different materials toimpart different handling characteristics to the guide catheter 105. Forexample, the outer layer may be made of or include softer materials topromote flexibility of the guide catheter 105. In other examples, theouter layer may be made of or include stiffer materials to promotepushability and/or torqueability of the guide catheter 105. In yet otherexamples, the outer layer may include lubricious materials to reducefriction between the guide catheter 105 and the body lumen of thepatient. The outer layer may include PEBA, polytetrafluoroethylene(“PTFE”), polyetheretherketone (“PEEK”), other polymers, thermoplasticpolyurethane (“TPU”), polyethylene with pebble stone surface, siliconeoil stainless steel, Nitinol, other metals, or combinations thereof. Inat least one embodiment, the outer layer may include a plurality of PEBA materials having different durometers.

In some embodiments, the outer layer of guide catheter 105 may alsoinclude a radiopaque marker to improve visualization of guide catheter105 during a medical procedure. For example, the outer layer may includea barium sulfate (BaSO4), gold, platinum, platinum iridium, iodine,other radiopaque materials, or combinations thereof on a distal portionof guide catheter 105. In at least one embodiment, one or moreadditional radiopaque markers may be longitudinally located at one ormore intermediate locations along the length of guide catheter 105.

The curves of guide catheter 105 may be formed by any suitable means. Insome embodiments, one or more of the curves are preset so that the curveis formed by shape memory. For example, guide catheter 105 may becomprised of a flexible polymer material in which a curve is preset byheating. When guide catheter 105 is loaded on a guidewire, dilator,obturator or introductory device, the flexibility of guide catheter 105can allow it to follow the shape or path of the introductory device forproper positioning within the body. When the introductory device ispulled back and/or removed, guide catheter 105 can then resume the shapememory configuration which was preset into the catheter.

Alternatively, the curves may be formed or enhanced with the use of oneor more steering mechanisms. In some embodiments, the steering mechanismcomprises at least one control wire or pull wire attached to one of theguide catheter 105, wherein actuation of the steering mechanism appliestension to the at least one pull wire whereby the curve is formed. Thepull wires can extend through the central lumen or through individuallumens in the wall of guide catheter 105. It may be appreciated thatmore than one pull wire may extend through any given lumen. The presenceof each pull wire allows curvature of guide catheter 105 in thedirection of the pull wire. For example, when pulling or applyingtension to a pull wire extending along one side of the catheter, thecatheter will bend, arc or form a curvature toward that side. To thenstraighten the catheter, the tension may be relieved for recoilingeffects or tension may be applied to a pull wire extending along theopposite side of the catheter. Therefore, pull wires are oftensymmetrically placed along the sides of the catheter.

Thus, in some embodiments at least two pull wires are attached indiametrically opposed locations wherein applying tension to one of thepull wires curves the catheter in one direction and applying tension tothe pull wire attached in the diametrically opposed location curves thecatheter in another direction opposite to the one direction. Thediametrically opposed pull wires may be considered a set. Any number ofsets may be present in a catheter to provide unlimited directions ofcurvature. In some embodiments, the steering mechanism can comprise atleast four pull wires wherein two of the at least four pull wires areattached to the guide catheter in diametrically opposed locations andanother two of the at least four pull wires are attached to the guidecatheter in diametrically opposed locations. In other words, thecatheter may include two sets of pull wires, each set functioning in anopposing manner as described. When the two sets of pull wires arepositioned so that each pull wire is 90 degrees apart, the catheter maybe curved so that the distal end is directed from side to side and upand down. In other embodiments, the steering mechanism comprises atleast three pull wires, each pull wire symmetrically positionedapproximately 120 degrees apart. When tension is applied to any of thepull wires individually, the catheter is curved in the direction of thepull wire under tension. When tension is applied to two pull wiressimultaneously, the catheter is curved in a direction between the pullwires under tension. Additional directions may also be achieved byvarious levels of tension on the pull wires. It may be appreciated thatany number, combination and arrangement of pull wires may be used todirect the catheters in any desired direction.

In some embodiments, a portion of one of guide catheter 105 can compriseone or more articulating members. In this case, the at least one pullwire is attached to one of the articulating members so that the curve isformed by at least some of the articulating members. Each pull wire isattached to the catheter at a location chosen to result in a particulardesired curvature of the catheter when tension is applied to the pullwire. For example, if a pull wire is attached to the most distalarticulating member in the series, applying tension to the pull wirewill compress the articulating members proximal to the attachment pointalong the path of the pull wire. This results in a curvature forming inthe direction of the pull wire proximal to the attachment point. It maybe appreciated that the pull wires may be attached to any location alongthe catheter and is not limited to attachment to articulating members.Typically, the articulating members comprise inter-fitting domed ringsbut may have any suitable shape.

It may also be appreciated that curves in guide catheter 105 may beformed by any combination of mechanisms. For example, a portion of guidecatheter could form a curve by shape memory while a different portion ofguide catheter could form a curve by actuation of a steering mechanism.

The steering mechanisms may be actuated by manipulation of actuatorslocated on handle 110. The handle 110 can be connected with the proximalend of the guide catheter 105 and remains outside of the body. One ormore actuators or controls 120 can be provided on handle 110 and mayhave any suitable form, including buttons, levers, knobs, switches,toggles, dials, or thumbwheels, to name a few. When pull wires are used,each actuator may apply tension to an individual pull wire or to a setof pull wires. The handle may also include one or more lockingmechanisms configured to interface with, and selectively lock intoplace, one or more of the controls 120.

As further illustrated in FIG. 1, the leaflet cutting system 100 canalso include a hook catheter 130, which is positioned coaxially within,and extends through the length of the guide catheter 105. The hookcatheter 130 has a proximal end, which can also be operatively coupledto handle 110, and a distal end portion 135, which can be selectivelyadvanced beyond the distal end 115 of guide catheter 105. The hookcatheter 130 can also include one or more control lines (not shown) thatcan be operatively connected to control 120 of handle 110 forselectively applying a curve to the distal end portion 135 of hookcatheter 130 once it has been advanced to extend beyond the distal end115 of the guide catheter 105 (as discussed in additional detail below).

In at least one embodiment, the handle 110 can also include at least onecontrol 120 for actuating and/or adjusting one or more components of ahook catheter 130. As shown in FIG. 1, once the hook catheter 130 isadvanced to extend beyond the distal end 115 of the guide catheter 105,control 120 can be actuated to apply a curve to the distal end portion135 of hook catheter 130 to cause the distal end portion 135 to form aU-shaped or hook configuration. In at least one embodiment, the hookcatheter 130 is routable through the guide catheter 105 and retractableinto the guide catheter 105. The at least one control 120 may controlthe hook catheter's 130 extension from and retraction into the guidecatheter 105. Additionally or alternatively, the at least one control120 may control the curvature and/or extension of the distal end portion135 of the hook catheter 130.

In an alternate embodiment, instead of providing a separate controland/or control lines for selectively controlling the curvature of thedistal end portion 135 of hook catheter 130, the distal end portion 135of hook catheter 130 can comprise a shape-memory alloy (e.g.,nickel-titanium, copper aluminum-nickel, etc.) portion having apre-defined shape-memory shape, such as a hook shape. When withdrawnwithin the lumen of guide catheter 105, the distal end portion 135 ofhook catheter 130 may be constrained within, and conform to therelatively straight configuration of, guide catheter 105. However, whenthe distal end portion 135 of hook catheter 130 is advanced beyond thedistal end 115 of guide catheter 105, the distal end portion 135 of hookcatheter 130 may return to its pre-formed, shape-memory shape.

In this and other embodiments described herein, the inner or hookcatheter 130 should preferably have sufficient flexibility as to be ableto conform to bends formed by guide catheter 105. Additional flexibilityto accommodate bending may be provided in certain regions of hookcatheter 130 by a series of laser cuts formed in its outer wall. Inaddition, the inner or hook catheter 130 should also provide sufficientcompressive and/or tensile strength to permit forces to be transmittedthrough catheter 130, from the proximal end to the distal end,sufficient to cause the cutting portions of catheter 130 to cut throughthe leaflet tissue.

In at least one embodiment, one or more cutting mechanisms (see FIG. 2)may be routed through the guide catheter 105 and/or hook catheter 130. Acutting mechanism may extend from the hook catheter 130. The handle 110may include at least one control 120 that is operatively connected tothe cutting mechanism. In at least one embodiment, the at least onecontrol 120 is configured to provide selective actuation of the cuttingmechanism. In this and other embodiments described herein, components ofthe cutting mechanism may be formed from the same or differentmaterials, including but not limited to stainless steel or other metals,Elgiloy®, nitinol, titanium, tantalum, metal alloys or polymers.

FIG. 2 is a perspective view of an exemplary embodiment of a cuttingmechanism shown in use in association with a human heart, specificallythe mitral valve 205. The mitral valve 205 comprises an anterior mitralleaflet 210 and a posterior mitral leaflet 215. FIG. 2 also shows aninterventional implant (e.g., MitraClip®) 220, which has previously beenaffixed to the leaflets in an effort to reduce regurgitation. As shown,the affixation of implant 220 to the leaflets creates a first orifice222 and a second orifice 224 located on opposing sides of implant 220and between the anterior mitral leaflet 210 and the posterior mitralleaflet 215. And, as discussed above, if further treatment is requiredin the form of the installation of an artificial, replacement mitralvalve, the prior clip implant 220 must be detached from one or both ofthe leaflets before the replacement valve can be implanted.

As further illustrated in FIG. 2, the distal end 115 of the guidecatheter 105 can extend through an interatrial septum 200 of the heart.Once the distal end 115 of guide catheter 110 is properly positionedabove the mitral valve 205, the distal end portion 135 of the hookcatheter 130 may be advanced to extend beyond the distal end 115 ofguide catheter 110. In at least one embodiment, the hook catheter 130 isconfigured to extend from the distal end 115 of the guide catheter 105through the first orifice 222 of the mitral valve 205 (from an atrialside to a ventricle side), as shown in FIG. 2. One skilled in the artwill appreciate that the positioning of the guide catheter 105 and hookcatheter 130 in FIG. 2 is merely exemplary and the present invention isnot limited to the positioning shown.

With the distal end portion 135 of hook catheter 130 positioned withinthe left ventricle, a curve can be applied to the distal end portion 135of hook catheter 130 to form a U-shape, a hook or other suitable shape.As discussed above, this curve can be formed either with the use ofsteering control lines provided within hook catheter 130 and operativelycoupled to control 120 or by virtue of a pre-formed, shape-memorymaterial from which the distal end portion 135 of hook catheter isformed. In either event, once the hook or U-shape has been effectuated,then guide catheter 105 and/or the hook catheter 130 can be furthermanipulated to pull the system in a proximal direction and thereby drawthe distal end 132 of hook catheter 130 through the second orifice 224(from the ventricle to the atrial side). As the hook catheter 130 ispositioned, the curved or U-shaped portion is moved to one side or otherof the clip implant 220, so that a cutting portion (discussed furtherbelow) of the hook catheter 130 is positioned to one side or the otherof the clip implant 220 and into direct contact with the tissue ofeither the anterior or posterior leaflet located adjacent to the clipimplant 220.

As further illustrated in FIG. 2, hook catheter 130 also includes acutting mechanism 230 that is adapted to selectively cut the tissue ofone of the mitral valve leaflets adjacent to the clip implant 220. Inone embodiment, the cutting mechanism 230 is disposed on the outsidesurface of the hook catheter 130 along the inner radius of the curved orU-shaped portion thereof. The cutting mechanism 230 may comprise anexposed, elongate electrode strip configured to selectively provideradio frequency current energy to a portion of leaflet tissue of themitral valve 205, thereby cutting the portion of leaflet tissue. Theelectrode wire strip may comprise a metal material with low impedance.In at least one embodiment, the exposed electrode wire strip cancomprise platinum, iridium, silver, gold, or other suitable metalmaterial with relatively low impedance, or a combination thereof.

Hook catheter 130 can also include an electrical conductor (not shown)that extends along the its entire length, which conductor iselectrically coupled at a distal end 135 to the exposed electrode andwhich is also electrically coupled at is proximal end 140 to a sourcefor selectively applying electrosurgical energy, such as anelectrosurgical generator. For example, the electrical conductor canextend through a lumen or recess formed in the side wall of the hookcatheter 130 or could also take the form of an electrically conductivecoating applied to the interior or exterior surface of the hookcatheter. The exact form and location of the electrical conductor, aswell as the electrical couplings at either end is well within theknowledge of those skilled in the art.

In use, once the leaflet cutting system 100 is positioned with theU-shaped or curved distal end portion 135 of hook catheter 130 extendingthrough one orifice 222 and then back through the other orifice 224,then the system 100 is further manipulated to withdraw the entire system100 in a proximal direction until the exposed electrode strip located onthe inner radius of the U-shaped portion comes into contact with one ofthe leaflets located to one side or the other of the clip implant and,more particularly, until the exposed electrode strip comes in contactwith the leaflet tissue that is located adjacent to the clip implant220. At that point, electrosurgical energy is supplied to the exposedelectrode strip to cut through the leaflet tissue, thereby separatingthe affected leaflet from the clip implant 220. In some cases, if may benecessary to continue to manipulate the hook catheter 130, during theapplication of electrosurgical energy, to cut through all of the leaflettissue between the first orifice 222 and the second orifice 224. Forexample, such further manipulation may include further movement in aproximal direction, rotation of the hook catheter 130 about the longaxis of guide catheter 105 and/or a combination of both. Once cutting ofthe leaflet is complete, the electrosurgical energy can be shut off, thehook catheter 130 can be withdrawn back into the guide catheter 105, andthen the guide catheter 105 can be further withdrawn back through theseptum and patient's other vasculature and removed entirely from thepatient.

In other embodiments, instead of using an electrode and electrosurgicalenergy to effectuate the cutting of leaflet tissue, the hook catheter130 may be provided with a sharpened, cutting edge or blade (not shown)formed in the inside radius of the curved or U-shaped portion. Then,when the system is moved in a proximal direction with the hook catheter130 extending between the first orifice 222 and the second orifice 224,the sharpened, cutting edge or blade can mechanically cut through theleaflet tissue and thereby separate the clip implant 220 from theaffected leaflet. In still other embodiments, the electrode,electrosurgical energy and a sharpened, cutting edge may be combined toprovide cutting the leaflet tissue by a combination of mechanicalcutting and/or by concentrating applied electrosurgical energy to thesharpened edge.

In any case, the hook catheter 130 is positioned against the targetedleaflet tissue, thereby positioning the cutting mechanism 230 forcutting. Additionally or alternatively, the cutting mechanism 230 may bepositioned against the leaflet tissue by tightening the unexposedportion of the electrode wire strip that extends to the handle 110. Thetightening may cause the exposed portion of the electrode wire strip toconstrict, causing it to move away from the portion of the inner radiusof the hook catheter 130 towards the leaflet tissue. One skilled in theart will appreciate that the cutting mechanism 230 shown in FIG. 2 isexemplary and therefore not limited to the size, shape, or positioningillustrated.

As further illustrated in FIG. 2, an optional stabilizing catheter 225may also be used to provide additional stability to the system, whichcan aid in the proper movement, manipulation, positioning and placementof the hook catheter 130 relative to the mitral valve 205 and clipimplant 220. Stabilizing catheter 225 can be configured to extend fromthe distal end 135 of the hook catheter 130 and engage against tissue atthe mitral valve 205, thereby stabilizing the distal end 135 of the hookcatheter 130 relative to the mitral valve. The stabilizing catheter 225is not limited to the size, shape, or positioning of that shown in FIG.2.

FIG. 3 is a perspective view of an alternative embodiment of leafletcutting system 100. The embodiment illustrated in FIG. 3 is similar inall respects to the embodiment discussed above in connection with FIG.2, except that the form and location of the cutting electrode isdifferent. Similar to FIG. 2, FIG. 3 shows the distal end 115 a of theguide catheter 105 a extending through the interatrial septum 200 a ofthe heart. The hook catheter 130 a may be routed through and extendingfrom the guide catheter 105 a. In at least one embodiment, the distalend portion 135 a of hook catheter 130 a is configured to extend fromthe distal end 115 a of the guide catheter 105 a through the firstorifice 222 a of the mitral valve 205 a (from an atrial side to aventricle side). One skilled in the art will appreciate that thepositioning of the guide catheter 105 a and hook catheter 130 a in FIG.3 is mere exemplary and the present invention is not limited to thepositioning shown.

FIG. 3 shows that the distal end portion 135 a of the hook catheter 130a may not extend through the second orifice 224 a of the mitral valve205 a (from the ventricle side to the atrial side). In at least oneembodiment, the hook catheter 130 a can also extend back through orpartially through the second orifice 224 a. In this embodiment, however,the cutting mechanism 230 a is not located within the inner radius ofthe U-shaped portion. Rather, the cutting electrode 230 a extends fromthe distal end 135 a of the hook catheter 130 a, thereby engaging withthe leaflet tissue. In at least one embodiment, the cutting mechanism230 a is routed through the guide catheter 105 a and hook catheter 130a. As stated above, at least one control may be operatively connected tothe cutting mechanism and may additionally be configured to provideselective actuation of the cutting mechanism 230 a. In at least oneembodiment the at least one control is further configured to rotate thehook catheter 130 a around a horizontal arc such that leaflet tissue iscut in a horizontal arc (as schematically indicated by the dotted line232 a shown in FIG. 4).

In at least one embodiment the cutting mechanism 230 a can comprise awire. The wire may comprise a sharp edge or be configured to selectivelyprovide radio frequency current energy to the leaflet tissue, therebycutting the leaflet tissue. The wire may comprise a metal material withlow impedance (e.g., platinum iridium, silver, gold, or other suitablemetal material with low impedance, or a combination thereof).

FIG. 4 is a top perspective view of the embodiment shown in FIG. 3.Similar to FIG. 3, FIG. 4 shows the distal end 115 a of the guidecatheter 105 a extending through the interatrial septum 200 a of theheart, and the hook catheter 130 a routed through and extending from thedistal end 115 a of guide catheter 105 a. FIG. 4 also shows the hookcatheter 130 a extending through the first orifice 222 a of the mitralvalve 205 a (from an atrial side to a ventricle side). One skilled inthe art will appreciate that the positioning of the guide catheter 105 aand hook catheter 130 a in FIG. 4 is mere exemplary and the presentinvention is not limited to the positioning shown.

Like FIG. 3, FIG. 4 shows that the distal end 132 a of the hook catheter130 a does not extend through the second orifice 224 a of the mitralvalve 205 a (from the ventricle side to the atrial side). Rather, onlythe cutting mechanism or electrode 230 a in FIG. 4 extends from thedistal end 132 a of the hook catheter 130 a and through the secondorifice 224 a, thereby engaging with the leaflet tissue. In at least oneembodiment the cutting mechanism 230 a comprises a wire. The wire maycomprise a sharpened, cutting edge and/or be configured to selectivelyprovide radio frequency current energy to the leaflet tissue, therebycutting the leaflet tissue. The wire may comprise a metal material withlow impedance (e.g., platinum iridium, silver, gold, or other suitablemetal material with low impedance, or a combination thereof). Once thehook catheter 130 a and cutting electrode 230 a are properly positioned,electrosurgical energy can then be applied to cutting electrode 230 a,and hook catheter 130 a can be rotated about its axis. As will beappreciated, rotation of hook catheter 130 a about its axis will causecutting electrode to travel in an arcuate path (as graphicallyillustrated at 232 a in FIG. 4), cutting through the leaflet tissuelocated adjacent to the clip implant 220 a and separating the first andsecond orifices.

Finally, FIG. 5 illustrates yet one more embodiment of a leaflet cuttingsystem 100. This embodiment is very similar to the embodiment discussedabove in relation to FIGS. 3 and 4 and relevant portions of thedisclosure above are hereby incorporated herein by reference. In thisembodiment, however, there is no need for a separate hook catheter. Asshown, after guide catheter 105 b passes through the septum 200 b, it isguided through the first orifice 222 b. Once the steerable portion 117 bof guide catheter 105 b is positioned within the left ventricle, thencontrol 120 b used to bend the steerable portion 117 b of guide catheter105 b in a hook or U-shape, so that the distal end 115 b of guidecatheter 105 b is pointing back in the direction of the atrium asillustrated. Then, the cutting electrode 230 b is advanced to extendbeyond the distal end 115 b of guide catheter 105 b and extend throughthe second orifice 224 b. Once the cutting electrode 230 b is properlypositioned within second orifice 224 b, electrosurgical energy can beapplied to the cutting electrode 230 b and guide catheter 105 b can berotated thereby causing electrode 230 b to cut through the leaflettissue, separating the clip implant 220 b from the affected leaflet.

With any or all of the foregoing embodiments, one or more components ofthe leaflet cutting system can also include one or more radiopaqueand/or echogenic markers to aid in the visualization of such componentsduring a procedure. For example, one or more radiopaque and/or echogenicmarkers can be provided on the distal end 115 and/or the steerableportion 117 of the guide catheter 105. Similarly, one or more radiopaqueand/or echogenic markers can be provided on the hook catheter 130,particularly markers showing the boundaries of the cutting electrodes.

In at least one embodiment, the cutting mechanism 230 is configured tocut a portion of the anterior mitral leaflet 210. Accordingly, theinterventional implant 220 may remain attached to the posterior mitralleaflet 215 thereby reducing the risk that the interventional implant220 will interfere with functioning of the left ventricular outflowtract. Additionally or alternatively, the posterior mitral leaflet 215may be cut with little or acceptable risk of left ventricular outflowtract interference. In at least one embodiment, the interventionalimplant 220 is removed from the patient.

One skilled in the art will appreciate that the present invention is notlimited to use within the mitral valve 205. The cardiac valve could alsobe the tricuspid aortic, pulmonic valve, etc. More generally, theembodiments described herein may be applied in other implementationsinvolving removal of a previously implanted or deployed device fromtissue. Further, although FIGS. 2-3 show the guide catheter 105extending through the interatrial septum 200, the present invention isnot limited to use via a transseptal approach. Any suitable deliveryapproach may be used, including transfemoral, radial, transjugular, ortransapical.

The foregoing devices and systems are also adapted to perform a methodof cutting leaflet tissue. Such methods of cutting cardiac valve tissueat a cardiac valve within a body may include positioning a guidecatheter, having a proximal and a distal end, within the left atriumtransseptally such that the distal end of the guide catheter ispositioned above a cardiac valve. The method may also comprise routing ahook catheter through the guide catheter such that the hook catheterextends distally beyond the distal end of the guide catheter through afirst orifice of the cardiac valve, wherein the cardiac valve isassociated with an interventional implant that approximates adjacentleaflets of the cardiac valve, and a cutting mechanism extends from thehook catheter. The method may further comprise positioning the hookcatheter to place the cutting mechanism into contact with leaflet tissuelocated adjacent to the interventional implant and actuating the cuttingmechanism to cut at least one leaflet of the approximated adjacentleaflets.

In describing the various embodiments above, the description may attimes have explicitly discussed one particular mitral valve leaflet,such as anterior leaflet 210. It should be understood and appreciated,however, that the invention is not intended to be limited to eitherspecific leaflet, but instead can be used to cut either anterior leaflet210, posterior leaflet 215, or both.

It should also be understood that the order of manipulation ofcomponents of the various embodiments as described above are provided asrepresentative examples only, and changes in the order of manipulationthat may be readily understood by those skilled in the art are intendedto be encompassed within the scope of this disclosure.

Similarly, while many of the embodiments discussed above contemplatemechanical cutting of leaflet tissue by means of sharpened edges of acutting element, it should be further understood that such embodimentscould also be adapted to include suitable electrical connections betweenthe cutting element and a source of electrosurgical energy so that suchcutting elements may accomplish cutting of tissue by mechanical cutting,by the application of electrosurgical energy to surrounding tissuethrough the cutting element, or by a combination of both.

Also, with any or all of the foregoing embodiments, one or morecomponents of the leaflet cutting system can also include one or moreradiopaque and/or echogenic markers to aid in the visualization of suchcomponents during a procedure. For example, one or more radiopaqueand/or echogenic markers can be provided on the distal end 115 and/orthe steerable portion 117 of the guide catheter 105. Similarly, one ormore radiopaque and/or echogenic markers can also be provided on variouscomponents of the different embodiments of the cutting mechanismsdescribed above, including, but not limited to such markings beingprovided on the distal ends of the inner catheter, hypotube, cuttingblades, etc.

One skilled in the art will appreciate that the present invention is notlimited to use within the mitral valve. The cardiac valve could also bethe tricuspid aortic, pulmonic valve, etc. More generally, theembodiments described herein may be applied in other implementationsinvolving removal of a previously implanted or deployed device fromtissue. Further, although figures show the guide catheter 105 extendingthrough the interatrial septum 200, the present invention is not limitedto use via a transseptal approach. Any suitable delivery approach may beused, including transfemoral, radial, transjugular, or transapical.

Following are some further example embodiments of the invention. Theseare presented only by way of example and are not intended to limit thescope of the invention in any way.

Embodiment 1. A system for cutting leaflet tissue at a cardiac valve,comprising: a guide catheter having a proximal end and a distal end,wherein the distal end of the guide catheter is steerable to a positionabove a cardiac valve, a hook catheter having a proximal end and adistal end, the hook catheter configured to extend from the distal endof the guide catheter through a first orifice of the cardiac valve; acutting mechanism extending from the hook catheter, the cuttingmechanism configured to cut a portion of leaflet tissue of the cardiacvalve, and a handle coupled to the proximal end of the guide catheter,the handle comprising at least one control operatively connected to thecutting mechanism.

Embodiment 2. The system of embodiment 1, further comprising astabilizing catheter configured to extend from the distal end of thehook catheter, thereby stabilizing the distal end of the hook catheterrelative to the cardiac valve.

Embodiment 3. The system in any of embodiments 1 to 2, wherein thedistal end of the hook catheter is configured to extend at leastpartially through a second orifice of the cardiac valve.

Embodiment 4. The system in any of embodiments 1 to 3, wherein the atleast one control is configured to provide selective actuation of thecutting mechanism.

Embodiment 5. The system in any of embodiments 1 to 4, wherein the atleast one control is further configured to rotate the hook catheteraround a horizontal arc such that leaflet tissue of the cardiac valve iscut in a predefined arc.

Embodiment 6. The system in any of embodiments 1 to 5, wherein thecutting mechanism is disposed on at least a portion of an inner radiuson an outside surface of the hook catheter.

Embodiment 7. The system in any of embodiments 1 to 6, wherein thecutting mechanism comprises an electrode wire strip configured toselectively provide radio frequency current energy to the portion ofleaflet tissue of the cardiac valve, thereby cutting the portion ofleaflet tissue.

Embodiment 8. The system in any of embodiments 1 to 7, wherein theelectrode wire strip comprises a metal material with low impedance.

Embodiment 9. The system in any of embodiments 1 to 8, wherein theelectrode wire strip comprises platinum iridium, silver, gold, or acombination thereof.

Embodiment 10. The system in any of embodiments 1 to 9, wherein theelectrode wire strip comprises an exposed portion disposed on at leastthe portion of the inner radius on the outside surface of the distal endof the hook catheter and an unexposed portion disposed within the hookcatheter that extends to the handle.

Embodiment 11. The system in any of embodiments 1 to 10, wherein thecutting mechanism comprises a wire that is routable from the handlethrough the guide catheter and hook catheter such that the wire isconfigured to extend beyond the distal end of the hook catheter andretract into the hook catheter.

Embodiment 12. The system in any of embodiments 1 to 11, wherein thewire comprises a sharpened edge.

Embodiment 13. The system in any of embodiments 1 to 12, wherein thewire is configured to selectively provide radio frequency current energyto the portion of leaflet tissue of the cardiac valve, thereby cuttingthe portion of leaflet tissue.

Embodiment 14. The system in any of embodiments 1 to 13, wherein thewire comprises a metal material with low impedance.

Embodiment 15. The system in any of embodiments 1 to 14, wherein thewire comprises platinum, iridium, silver, gold, or a combinationthereof.

Embodiment 16. A system for cutting leaflet tissue at a cardiac valve,comprising, a guide catheter having a proximal end and a distal end,wherein the distal end of the guide catheter is guided to a positionabove a cardiac valve transseptally, a hook catheter having a proximalend and a distal end, wherein the hook catheter is routable through theguide catheter and configured to extend beyond the distal end of theguide catheter through a first orifice of the cardiac valve and retractinto the guide catheter, and a cutting mechanism routable through theguide catheter and the hook catheter and configured to cut a portion ofleaflet tissue of the cardiac valve.

Embodiment 17. The system of embodiment 16, wherein the distal end ofthe hook catheter is configured to extend at least partially through asecond orifice of the cardiac valve.

Embodiment 18. The system in any of embodiments 16-17, furthercomprising a stabilizing catheter that is routable through the guidecatheter and hook catheter such that the stabilizing catheter isconfigured to extend beyond the distal end of the hook catheter, therebystabilizing the distal end of the hook catheter relative to the cardiacvalve.

Embodiment 19. The system in any of embodiments 16-18, wherein thecutting mechanism comprises an electrode wire strip having an exposedportion disposed on an inner radius on an outside surface of the distalend of the hook catheter and an unexposed portion disposed within thehook catheter.

Embodiment 20. The system in any of embodiments 16-19, wherein theelectrode wire strip is configured to selectively provide radiofrequency current energy to the portion of leaflet tissue of the cardiacvalve, thereby cutting the portion of leaflet tissue.

Embodiment 21. The system in any of embodiments 16-20, wherein thecutting mechanism comprises a wire that is routable through the guidecatheter and hook catheter such that the wire is configured to extendbeyond the distal end of the hook catheter and retract into the hookcatheter.

Embodiment 22. The system in any of embodiments 16-21, wherein the wirecomprises a sharpened edge.

Embodiment 23. The system in any of embodiments 16-22, wherein the wireis configured to selectively provide radio frequency current energy tothe portion of leaflet tissue of the cardiac valve, thereby cutting theportion of leaflet tissue.

Embodiment 24. A method of cutting leaflet tissue at a cardiac valvewithin a body, comprising: positioning a guide catheter, having aproximal and a distal end, within the left atrium transseptally suchthat the distal end of the guide catheter is positioned above a cardiacvalve, routing a hook catheter through the guide catheter such that thehook catheter extends distally beyond the distal end of the guidecatheter through a first orifice of the cardiac valve, wherein thecardiac valve is associated with an interventional implant thatapproximates adjacent leaflets of the cardiac valve, and a cuttingmechanism extends from the hook catheter, and actuating the cuttingmechanism to cut at least one leaflet of the approximated adjacentleaflets.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges that come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

We claim:
 1. A system for cutting leaflet tissue at a cardiac valve,comprising: a guide catheter having a proximal end and a distal end,wherein the distal end of the guide catheter is steerable to a positionabove a cardiac valve; a hook catheter having a proximal end and adistal end, the hook catheter configured to extend from the distal endof the guide catheter through a first orifice of the cardiac valve; acutting mechanism extending from the hook catheter, the cuttingmechanism configured to cut a portion of leaflet tissue of the cardiacvalve; and a handle coupled to the proximal end of the guide catheter,the handle comprising at least one control operatively connected to thecutting mechanism.
 2. The system of claim 1, further comprising astabilizing catheter configured to extend from the distal end of thehook catheter, thereby stabilizing the distal end of the hook catheterrelative to the cardiac valve.
 3. The system of claim 1, wherein thedistal end of the hook catheter is configured to extend at leastpartially through a second orifice of the cardiac valve.
 4. The systemof claim 1, wherein the at least one control is configured to provideselective actuation of the cutting mechanism.
 5. The system of claim 1,wherein the at least one control is further configured to rotate thehook catheter around a horizontal arc such that leaflet tissue of thecardiac valve is cut in a predefined arc.
 6. The system of claim 1,wherein the cutting mechanism is disposed on at least a portion of aninner radius on an outside surface of the hook catheter.
 7. The systemof claim 6, wherein the cutting mechanism comprises an electrode wirestrip configured to selectively provide radio frequency current energyto the portion of leaflet tissue of the cardiac valve, thereby cuttingthe portion of leaflet tissue.
 8. The system of claim 7, wherein theelectrode wire strip comprises a metal material with low impedance. 9.The system of claim 8, wherein the electrode wire strip comprisesplatinum, iridium, silver, gold, or a combination thereof.
 10. Thesystem of claim 7, wherein the electrode wire strip comprises an exposedportion disposed on at least the portion of the inner radius on theoutside surface of the distal end of the hook catheter and an unexposedportion disposed within the hook catheter that extends to the handle.11. The system of claim 1, wherein the cutting mechanism comprises awire that is routable from the handle through the guide catheter andhook catheter such that the wire is configured to extend beyond thedistal end of the hook catheter and retract into the hook catheter. 12.The system of claim 11, wherein the wire comprises a sharpened edge. 13.The system of claim 11, wherein the wire is configured to selectivelyprovide radio frequency current energy to the portion of leaflet tissueof the cardiac valve, thereby cutting the portion of leaflet tissue. 14.The system of claim 13, wherein the wire comprises a metal material withlow impedance.
 15. The system of claim 14, wherein the wire comprisesplatinum, iridium, silver, gold, or a combination thereof.
 16. A systemfor cutting leaflet tissue at a cardiac valve, comprising, a guidecatheter having a proximal end and a distal end, wherein the distal endof the guide catheter is guided to a position above a cardiac valvetrans septally; a hook catheter having a proximal end and a distal end,wherein the hook catheter is routable through the guide catheter andconfigured to extend beyond the distal end of the guide catheter througha first orifice of the cardiac valve and retract into the guidecatheter; and a cutting mechanism routable through the guide catheterand the hook catheter and configured to cut a portion of leaflet tissueof the cardiac valve.
 17. The system of claim 16, wherein the distal endof the hook catheter is configured to extend at least partially througha second orifice of the cardiac valve.
 18. The system of claim 16,further comprising a stabilizing catheter that is routable through theguide catheter and hook catheter such that the stabilizing catheter isconfigured to extend beyond the distal end of the hook catheter, therebystabilizing the distal end of the hook catheter relative to the cardiacvalve.
 19. The system of claim 16, wherein the cutting mechanismcomprises an electrode wire strip having an exposed portion disposed onan inner radius on an outside surface of the distal end of the hookcatheter and an unexposed portion disposed within the hook catheter. 20.The system of claim 19, wherein the electrode wire strip is configuredto selectively provide radio frequency current energy to the portion ofleaflet tissue of the cardiac valve, thereby cutting the portion ofleaflet tissue.
 21. The system of claim 16, wherein the cuttingmechanism comprises a wire that is routable through the guide catheterand hook catheter such that the wire is configured to extend beyond thedistal end of the hook catheter and retract into the hook catheter. 22.The system of claim 21, wherein the wire comprises a sharpened edge. 23.The system of claim 21, wherein the wire is configured to selectivelyprovide radio frequency current energy to the portion of leaflet tissueof the cardiac valve, thereby cutting the portion of leaflet tissue. 24.A method of cutting leaflet tissue at a cardiac valve within a body,comprising: positioning a guide catheter, having a proximal and a distalend, within the left atrium transseptally such that the distal end ofthe guide catheter is positioned above a cardiac valve; routing a hookcatheter through the guide catheter such that the hook catheter extendsdistally beyond the distal end of the guide catheter through a firstorifice of the cardiac valve, wherein the cardiac valve is associatedwith an interventional implant that approximates adjacent leaflets ofthe cardiac valve, and a cutting mechanism extends from the hookcatheter; and actuating the cutting mechanism to cut at least oneleaflet of the approximated adjacent leaflets.